Refrigerating apparatus



A. T. MARSHALL.

REFRIGERATING APPARATUS.

' APPLICATION FILED 0CT=29,- 19l9.

1,%25,265, V Patented. Aug. 8, 19220 2 SHEETS-SHEET I.

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INVENTOR H l ,1 "w I BY i ATTORNEY5 A. T. MARSHALL.

REFRIGERATING APPARATUS.

APPLICATION FlLED ocr. 29, m9.

1 Ag5 2 5 g Patented Aug. 8 1922.

2 SHEETSSHEET 2.

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ALBERT 'r. MARSHALL, or nan'rronn connects-roar, ASSIGNOR T AUTOMATIC nnrmennn'rnve comrnnv, or nmarronn CONNECTICUT; A conronamron or NEW JERSEY.

sermon-RATING APPARATUS. v

Specification of Letters Patent. Patented Aug. 8, T922.

Application filed was 29, 1919. serial-no. 334,286.

To' all whom it may concern: 7

Be it known that I, ALBERT T. MARSHALL,

"a citizen of the United States, residing at Hartford, county of Hartford, and State of Connecticut, haveinvented certain new and useful Improvements n Refrigerating Apparatus, of which the following is a specification. p

This invention relates to refrigerating apparatus in which' therefrigerant in a gaseous state, is compressed into a fluid condition and then expanded under reduced pressure to absorb heat as it returns from the fluid state-to a gaseous condition.

The object of this invention is to provide improved apparatus for controlling the refrigerating process by means of the variation in pressure of the refrigerant in its expanded condition. Une of the objects of the present invention is to provide improved means for utilizing the relative variations inpressure in the refrigerating coil andthermostatic chamber provided therefor, for securing greater efliciency and economy of operation: Other and more specific ob jects of invention will appearin the specification and be pointed out in the-appended claims, reference being had to the accompansion valve partsbeing shown in elevation. r

. Referring more particularly to the draw-v ings in the embodiment of my invention shown therein, a motor 1 is connected by a j belt.2 with a wheel 3 which'is keyed toa counter-shaft 4 which carries a pulley 5,

' said pulley 5 being connected by a belt 6 I ciprocable plunger 44, a diaphragm being secu'redbetween its upper end and the lower portion 44*-of a yoke which is yieldablyv mounted upon a slide or cross head 46 having threaded connection with a stem 47.

The yoke 48' of which the lower portion 44 END provided with a with the fly wheel 7 which is keyed toa compressor shaft 8. Said compressor is cylinder 9 from which a a condenser 11, said condenser discharging through a pipe 12 into a receiver 13 for the condensed refrigerant.

pipe 10 leads to Leading'from the receiver 13 is a pipe 14 -'which' may be made of suitable size and capacity to supply any desired number of refrigerating units of which only two are shown on the drawings. Said units with their connections are substantially similar in the present embodiment of my invention so that a description of one will make the system readily understood as well as the character of the process carried on thereby. The lower branch 16 of said pipe includes a hand valve 17, the housing 18 for a motor operated Valve, the housing 19 for an eX- pansion valve and another hand valve 20. Connected up with the hand valve 20, is a refrigerating coil 21, which is provided near its outlet end, with a thermostatic cylinder .or chamber 22 from which a pipe 23 leads to a diaphragm housing 24 arranged above the valve housing 19. A positive main 25 is connected by a wire 26 to a thermostatic switch 27 which is operated by changing temperatures ingthe room containing refrigerating coil 21. A wire 28'leads from thermostatic switch 27 to one terminal of a motor contained in housing 29which is disposed above the valve housing 18.

centric cam' 33.

A wire 30 connects the other terminal o'f'said' motor to a negative main. 31. As shown in F igLire-3, the motor in housing 29 is adapted to operate-a shaft 32 which carries an 'ec-" Said cam 33 is suitably Y is pressed upon by the head35 of a stem 36 I which is reciproca-bly mounted in'a spider .37, aj'spring 38 being interposed between said h'ad35 and spider 37 for. exerting this pressure. Said valve stem 36 is provided at its other end with lugs 39 which.'serve to holdthat end central to the bore ofthe' pipe 16.

The balanced pressure valve is shown in its preferred embodiment in Figure 4. Thus the valve housing 19 is provided with an inlet port or opening 40 into. i

which opens the pipe section 16 leading from valve housing 18. A passage 41 leads from the opening 40 to a valve port or openin 42 which is presented downwardly, A va ve point 43 is adj ustably mounted in a reinspreferably constitutes an integral part,'rests upon a spring 49 carried by the slide or cross head 46. Said plunger 44 is provided with an opening 50 which permitsit I to be reciprocated by diaphragm 45. This opening 50 is in open communication with valve port 42 whenever valve 43 is retracted.

The main chamber 51 in valve housing 19 has i open communication by means of a port 52, with a channel 53 which leads, to hand valve and refrigerating coil 21. It will be understood from Figure 4 that the pipe 23 transmits fluid pressure from thermostatic chamber 22 to an inlet port 54 which'opens into the diaphragm chamber above the diaphragm 45. Said diaphragm is therefore subjected on one side to pressure obtaining in thermostatic chamber 22 and on its other side to the pressure existing in refrigerating coil '21. A balanced pressure control is thereby obtained which enables the system to be regulated with extreme nicety and made 5p operate with a high degree of efficiency.

s shown in Figure 1, a line wire 55 leads from the positive main 25 to a branch wire 56 which includes a fuse 57, an overload switch 58, and a high pressure cut-off switch 59. A resistance 60 is also connected up in this branch line in series with one terminal of a solenoid 61, the other terminal of said solenoid being connected by a wire 62 to another wire 63 which is connected to a back pressure switch 64. Said-switch a contact 69 which is connected by a wire 70 to the wire 67'. A maintaining circuit for, solenoid 61 is thus established which does not include the back pressure switch 64. At the same time, a bridge contact71 ,which is also moved by the -plunger 68, is

moved into position to close a gap in the main energizing circuit of motor 1. After motor 1 has been running for a period of time, conditions in the system will be changed in such a way that the back pres- Solenoid 61 is thereby short circuited, the i sure switch will be moved from contact 65 so that the maintenance of, the motor energizing circuit will depend alone upon solenoid 61.. Eventually said contact 64 will be moved sufliciently to cover a contact '74. This closes a shunt circuit from line wire 55, including fuse 57, switches 58 and 59, resistance 60, a resistance 72, wire 73, contact 74, switch 64, wire 63, wire 62, bridge. contact 68, wire and wire 67.

plunger '68 drops, and the motor comes to rest. Leading from each of the refrigerat-' ing coils 21, is a pipe 75 which is connected to a return pipe 76 which leads back to the compressor cylinder 9. A branch el bow 77 is connected to the return pipe 76 and at its upper end opens into a diaphragm housin 78. As shown in Figure 2, said elbow 77 opensupwardly into a chamber 79 below a diaphragm 80. A'plunger 81 is provided with an enlarged-head 82 which bears against the diaphragm under the pressure of a compression spring 83, which is interposed between a collar 84 and a fixed guide. 85. Near its lower end, said plunger is provided with a recess or opening 86. into which extends the shorter arm 87 of the back pressure switch lever which is pivoted at 88. The longer arm 89 of said switch lever carries the back pressure operated switch 64. Interposed between the lever arm 89 and diaphragm housing 78, isa spring 90 which causes the lever arm 87 to maintain a downward pressure on the plunger 81. Whenever the contact 64 is brought into engagement with contact 65 for setting up the motor operating circuits, it is held in circuit closing position by means of a magnet 91 which is connected up in the conductor 66. In a similar manner, a magnet 92 is connectedup in the conductor 73 for holding the contact 64 in engagement with contact 74 until diaphragm 80 is forced upwardly.

In the operation of this improved system, let it be assumed that the compressor is at rest and that all refrigerating rooms have become warmed up sufficiently to permit the thermostatic switch 27 to close. An

energizing circuit being closed through 25,

26, 27, 28, 29, 30 and 31, motor valve 34 is opened. By reason of "the slightly heated suction end of the refrigerating coil, the

pressure of fluid in thermostatic chamberceiver 13 is in open communication with refrigerating coil 21. Diaphragm 80 being moved upwardly-by the back pressure in pipe 76, spring contact 64 is brought to bear on contact 65 and;the motor is started by the circuits pointed out above. pumping; action which is thus 'set up, is continued under normal conditions until the back pressure in pipe 76 drops sufficiently, after all of the ammonia circuits have been cut off,.to permit diaphragm 80 to be depressed and the contact switch 64 to come into engagement with upper contact 74. This stops the motor by short circuiting the solenoid 61 and permitting bridge contact 71 to break the motor energizing circuit. It will be understood from the foregoing description that in addition to the controlof refrigerant by means of the mo- The - thereby, that coil supply or, if all operative controls.

1. re eases tor operated valve 34 which depends upon temperature conditions in the room which contains or is cooled by the refrigerating coil or coils 21, there are several other co- After the refrigerating process has been sufficiently extended in any coil, the temperature condition produce reacts to automatically disconnect from the system so that the supply then economized for any that may be requiring a the coils are automatically cut off, it is held in reserve for future needs of refrigerant is remaining colls the circuit for this series being peratures,

Fur-

placed in parallel with other circuits.

thermore one or more compressors maybe used in parallel between the suctlon' line in any of the coils in the system. On the 'other hand',,in order to secure a more sensitive control of the refrigerating fluid supply for maintaining the entire superficial area of the refrigerating coil as an active cooling surface, the expansion valve is made to depend upon the relative pressures of the fluid in said, refrigerating coil and in the thermostatic chamber 22 *which surrounds the last section of said refrigerat-' ing coil.

The operation of the compressor 9 is under the control of pressure variations within the return pipe 76 of the system itself. Whenever a room reaches the lower temperature for which its thermostat is set, the motor valve is moved to closed position for shutting ofl', the corresponding coil 21. The, action of the compressor is thereupon further accentuated in reducing the back pressure in the return; pipe 76. -When the lower limit for which the backpressure regulator has "been set, is reached, the compressor is stopped and remains idle until the I back pressure has again risen sum: ciently to set the compressor into. action. It will'be seen therefore'that the refrigerating process varies with the general thermostatic condition in the room, with the thermostatic conditions immediately. surrounding the warmest portion of the refrigerating coil and with the back pressure conditions in the system itself'within the return pipe 7 6 which leads to the compressor. -[t w1ll furthermore be understood that a and the condensers.

The term refrigerating coil, as used 1n (1 the specification and claims, is intended to have the meaning usually understood in this art, namely, a single coil, or a plurality of coils operating as one coil in effect.

I claim: p v

1. In an automatic refrigerating system in combination, a compressor, a plurality ofrefrigerating coils, a supply pipe leading from said compressor and having a connection to each of said refrigerating coils, a

shut-ofl valve and an expansion valve at the inlet end of each of said refrigerating coils, thermostatic means located in proximity to each refrigerating coil for controlling the 'shut-ofl valve connected thereto, thermo-' static means located at the outlet end of each open up their motor valves. 1

pansion of this system which lends itself to arrangements of parallel, 1n series, or'partly partly in series.

small rooms or coils may be put into series in parallel and rooms and circuits in For example a number offor one circuit when it is not so important.

to hold them at accurately established 'tem thereto, a

refrigerating. coil for controlling the expansion valve connected thereto, a common return pipe connecting the outlet ends of said refrigerating coils to said compressor, and means controlled by the pressure in said return pipe for controlling the operation of said compressor.

2. Tu an automatic refrigerating system, a compressor, -a plurality. of refrigerating coils, a supply pipe leading from said compressor having a connection toeach of said refrigerating coils, a shut-off valve, and an expansion valve at the inlet end of each of said refrigerating coils, thermostatic means located in proximity to each refrigerating coil for controlling the shut-off valve connected thereto, a common return pipe'connecting the outlets of said refrigerating coils to said compressor, and a pressure responsive device in said common return pipe for controlling the operation of said compressor. '3. In an automatic refrigerating system, a compressor, a plurality of refrigerating coils, a supply pipe leading from said compressor having a connection to each of said refrigerating coils, a motor-operated shutoff valve and an expansion valve at the inlet end of each of' said refrigerating coils,

each refrigerating coil for controlling the motor-operated shut-off valve connected fluid pressure chamber surrounding a portion of each refrigerating coil near its outlet end and operably connected to the expansion valve at its inlet end for controlling the supply of refrigerant according to the temperature in said fluid pressure chamber, a common return pipe connectin the outlets of said refrigerating coils to sai compressor, and apressure responsive device in said 'commonreturn pipe for startpressure and stopping said motor at a presaid motor at a predetermined maximum determined minimum pressure in said return pipe.

4. In an automatic refrigerating system,

a compressor, a plurality of refrigerating coils, separate supply pipes and a common return pipe connectlng said compressor and said refrigerating coils, a shut-01f valve and an expansion valve in each of said separate supply pipes, a pressure responsive device located in said return pipe, a switch arm operated by said pressure responsive device, two spaced contacts adapted to be covered separately by said switch arm at difierent pressures in said return pipe, a motor for driving said compressor, an energizing circult for sa1d motor, a switch insaid energizing circuit, a;- solenoid for operating said switch, an energizing circuit for said solenoid coil including said switch arm and one of said spaced contacts for starting said motor at a predetermined pressure in said return pipe, a shunt circuit connected across said switch arm and said spaced contact for maintaining the energizing circuit of said solenoid when said switch arm is out of contact with both'of said spaced contacts, a

switch in said shunt circuit'operated' by said solenoid simultaneously with the switch in the said motor energizing circuit, and a sec-- ond shunt circuit connected across the terminals of said solenoid coil and including said switch arm and the second of said emes I spaced contacts for stopping said motor at another predetermined pressure in said re turn pipe.

5. In an automaticrefrigerating system, a compressor, a plurality of refrigerating coils, separate supply pipes and a common return pipe connecting said compressor and saidrefrigerating coils, a shut-off valve and an expansion valve in each of said separate supply pipes, a pressure responsive device in sa1d return pipe, a switch arm operated by said pressure responsive device adapted to contact with a fixed contact at a predetermined maximum pressure and adapted to contact with a second fixed contact at a-predetermined minimum pressure in said return pipe, a motor for driving said compressor,

an energizing circuit for said motor, a switch 1n sa1d energizing c1rcu1t, a solenoid for operating sa1d swltch, an energizing c1rcu1t for said solenoid coil including said switch 

